The stakes are too high to fool with mercurial candidates. And all too often it seems that politicians regard constituents as a zero-sum game. That is, they calculate how many supporters will they lose by adopting a certain position vs. how many unknowns might they gain.
Rubio has to see that he is rapidly losing his base - and not gaining a single voter in his misguided quest for amnesty. The rate at which he is falling suggests that he has done himself irreparable harm.
You are just fooling yourself, because Rubio is pandering to his base, the Florida Liberals. Rubio supporters simply lacked the judgement and integrity to to acknowledge their fantasies about Rubio.